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Tag: CD4

04.15.2013

HIV testing by DVD

A recent paper in Lab on a Chip describes using a DVD player as a diagnostic tool. The researchers convert the optical drive into a laser scanning device that can count the number of CD4+ cells. From Phys Org:

Aman Russom, senior lecturer at the School of Biotechnology at KTH Royal Institute of Technology in Stockholm, says that his research team converted a commercial DVD drive into a laser scanning microscope that can analyse blood and perform cellular imaging with one-micrometre resolution. The breakthrough creates the possibility of an inexpensive and simple-to-use tool that could have far-reaching benefits in health care in the developing world.
“With an ordinary DVD player, we have created a cheap analytical tool for DNA, RNA, proteins and even entire cells,” says Russom. The so-called “Lab-on-DVD” technology makes it possible to complete an HIV test in just a few minutes, he says.
In a proof of concept demonstration, the researchers collected cell-type CD4 + from blood and visualized it using the DVD reader technology. Enumeration of these cells using flow cytometry is now standard in HIV testing, but the practice has been limited in developing countries.
HIV testing currently uses flow cytometry, which requires expensive equipment. If the DVD technique proves reliable, HIV testing can be done much more cheaply.

03.15.2013

CD4 cells are instrumental in controlling HIV infection

HIV medication

A report in Science discusses how a subset of CD4 cells could prevent HIV from destroying the immune system:

HIV preferentially invades T lymphocytes that have CD4 receptors on their surfaces. The resulting destruction of CD4 cells over a decade or so cripples the immune system and is the hallmark of AIDS. But the process takes many years because the central memory cell, a type of CD4+ T lymphocyte known in shorthand as Tcm, churns out clones of itself and can almost refill the body’s pool of CD4 cells as fast as HIV drains it. However, the downside is that some infected Tcm cells become reservoirs of latent virus that rekindle infection if antiretrovirals (ARVs) are stopped.

The report is based on a series of studies of HIV patients. In the first study 75 HIV patients were split into three different groups and received antiretroviral medications within 5 days of taking a blood test. When their blood was analyzed 24 weeks later, the level of HIV-infected Tcm cells was almost extremely low or undetectable. In another study researchers looked at why some patients were better able to protect their CD4+ cells without antiretroviral treatment:

The study compared nearly 300 infected people who had low levels of HIV in their blood, two-thirds of whom received treatment. The researchers found that elite controllers stood out in part because their Tcm cells downregulated a key receptor that HIV needs for entry and were less permissive to HIV infection. Conversely, Kitchen noted that people whose immune systems did not rebound even though ARVs controlled their infections had Tcm cells with impaired function.

Check the source link for more.

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